Cold and our ACR Kuhmos

[twist-a-grip]

It's getting colder where I live and my limited knowledge knows that driving in the cold on track compounds is not good for the tires. Seems I've read that our Kuhmos and the like (PSC2s) can crack and cause early failure if they are driven or even stored in <40 degree temps. Should I just keep the ACR inside for the winter, or, since I have a heated garage, am I OK to drive it around on a cooler 40-50 degree day? Just replaced the fronts and don't want any problems when I hit the track in the spring.

[swexlin]

It was 35 degrees this past Saturday, and my buddy had his ACR on Kumhos over to C&C. He was very careful, and had no issues. Being CAREFUL is the key. Same with my Corsas. I've driven them on a 17 degree morning (not by choice), and had no issues. Just was careful.

[Voice of Reason]

Even if you're careful they could crack due to low temps. I think Corsas are supposed to be a no go below 50 but I've driven as low as 45*.

[genVer]

Just FYI The ACR supplement manual says not to store them below 20 degrees Fahrenheit and not to drive on them until they have been up to 50 degrees for at least 24 hours. http://viper.c-myweb.com/images/2016ACRsuppliment.pdf

[ViperJon]

I'll let you know how the Kumho's are I'm planning on going on a breakfast run this weekend and it's only going to be high 30's low 40's. :)
My garage is never below 60 though.

[mjorgensen]

Just FYI The ACR supplement manual says not to store them below 20 degrees Fahrenheit and not to drive on them until they have been up to 50 degrees for at least 24 hours. http://viper.c-myweb.com/images/2016ACRsuppliment.pdf

If that is truly the case FCA cannot deliver any ACR's during winter months, way colder than that going down the highway in a Reliable truck strapped down by the tires hen unloading in the snow and ice??? Hope they warranty tires damaged during delivery.

[commandomatt]

I have the same question but it's about storage, not driving.

My ACR is on its way from Woodhouse as we speak (Thanks Bill and Mark) and the only room I have at this time is in my storage building. Not heated

So I am thinking about jacking the car up and taking the tires to a heated area. Maybe also supporting the suspension so that it doesn't hang at full extension all winter

Any thoughts ?

[genVer]

I have the same question but it's about storage, not driving.

My ACR is on its way from Woodhouse as we speak (Thanks Bill and Mark) and the only room I have at this time is in my storage building. Not heated

So I am thinking about jacking the car up and taking the tires to a heated area. Maybe also supporting the suspension so that it doesn't hang at full extension all winter

Any thoughts ?

That's actually what the manual recommends. For me that means bringing them into the house if the temps drop below 20.

[TA Two Oh]

The daytime high temperature here today is -18C or 0 degrees F. It can snow here in every month, including July and August, although that's extremely rare. I've run R Comps since I bought my first set of 008R's in the 1990's. I won't say that I have the definitive answer for you but I will share what I've learned over the years.

To me, there are two issues with R Comps in the cold... a lack of grip, and damage to the tread.

I have seen dozens of RComp shod cars that had cracks in the tread that were caused by exposure to very cold temperatures. Once the tread is cracked, in my opinion, the tires are not safe for spirited driving. The interesting thing is that the cars I've seen with this issue were either new, or the damage had apparently been done when the car was new. In every case, the car had been shipped in the wintertime. Yet I've driven hundreds, possibly thousands, of miles on R Comps -008R's, R888's, Sport Cups, Cup 2's, R6's, R7's and Corsas without issues. (I do not own an ACR and I have not driven on the ACR 720's but I would be extremely surprised if, in this regard, they were different than all the other R Comps)

Last year when a bunch of us left for a track event at Miller Motorsport Park, it was below freezing for almost half the trip and my Corsas were fine... no cracking. How come? My guess is because they'd already been heat cycled a few times, like all the other R Comps I've run in cold temps. It's the only explanation I can come up with. So, I would suggest putting some cycles on them before subjecting them to freezing or below freezing temperatures. If your garage is warm, and you want to take your car out in the temperatures you describe, I don't see cracking being an issue. Tires heat up due to sidewall flexing at they roll, so since they're starting out warm, they will stay reasonably warm and therefore should be fine. To reiterate, all the damaged tires that I've seen were on cars that were shipped in the cold, without the benefit of sidewall flexing to keep them warm.

Your other issue will be grip. I don't consider this to be a problem either, as long as you're careful, drive like the other cars around you, and aren't rough with the controls. If you stomp on the gas, expecting similar grip to what you get on a warm day, you won't experience much acceleration. If you do so while turning, you may end up in a full Code Brown situation, or worse... crash your car. But it's absolutely possible to drive on R Comps in cold weather, even below freezing, without issue. I would absolutely drive your car. Just exercise some restraint and common sense.

I hope that helps!

[TA Two Oh]

One thing that I forgot to mention was that my garage is heated. I would definitely recommend storing R Comps inside if it's cold where you live and your garage isn't warm.

[Steve-Indy]

From the TireRack site found at: http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=220

"It is not recommended to drive on these types of tires at temperatures below 40 degrees F (5 degrees C).

It is recommended these types of tires be stored indoors at temperatures maintained at above 20 degrees F (-7 degrees C) when not in use.

Tires accidentally exposed to temperatures of 20 degrees F (-7 degrees C) or lower must be permitted to gradually return to temperatures of at least 40 degrees F (5 degrees C) for at least 24 hours before they are flexed by adjusting inflation pressures, mounting them on wheels, or using them to support, roll or drive a vehicle.

In order to allow gradual, uniform and thorough increase in tire temperature, these types of tires should be protected from direct sources of intense heat as they warm up. Do not apply localized heat, blow heated air directly on them, nor place them near a heat source.

Always inspect tires before use after storage periods.

While compound cracking is not a warrantable condition because it occurs as the result of improper use or storage, tires exhibiting compound cracking must be replaced."

[twist-a-grip]

Thanks guys - you are telling me exactly what I anticipated. Certainly know about cold tires and traction, but the feedback on tire damage was helpful. I agree that if they're warm leaving the garage, I should be OK.

[VENOM V]

I don't know about sub-freezing temps or storage, but at the track these Kuhmos are AMAZING in cold weather. Absolutely superior to MPSCs and every other R compound I've tracked in the cold. I tracked at Laguna. 1st session, 40 degrees F. 2nd session, still in the 40s, I turned a 1:34.2. That's very fast for my skill level. 3rd session, 1:34.1, in 50 degrees ambient. This is me working up and getting used to the ACR, first time at Laguna with it. I'm confident I will be faster when I return. My friend Darius ran a 1:32.2 same day in his stock ACR on Kuhmos. The tires suck at the track though at over 95 F, but in the cold they just kick ass.

Here's my write up with the details:

http://driveviper.com/forums/threads/11503-Laguna-Seca-First-Track-Day-in-the-Extreme-ACR

[ACR Steve]

Molecular compound changes in the rubber at freezing temps. Our rubber is so soft that when the tire gets that cold it hardens and its supper easy to tear.

When driving you are making heat in them even at freezing temps. The problem is when its sitting

[ek1]

Just FYI The ACR supplement manual says not to store them below 20 degrees Fahrenheit and not to drive on them until they have been up to 50 degrees for at least 24 hours. http://viper.c-myweb.com/images/2016ACRsuppliment.pdf

Actually it says that IF they have been subjected to temps below 20f, THEN they need to be warmed up in a 50f space for 24 hours. Which means that no damage will occur above 20f.

[BlueAdder]

I drove this morning and it was about 7C (42F or something) outside. I have to drive a mountain road as part of my commute and while I was patient and careful, I wasn't overly concerned with the Kuhmo.
Now if it was snowing, that'd be a different story.